package com.hmdp.service.impl;

import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisData;
import com.hmdp.utils.SystemConstants;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;

import java.time.LocalDateTime;
import java.util.*;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import static com.hmdp.utils.RedisConstants.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private CacheClient cacheClient;
    @Resource
    private IShopService shopService;
    @Override
    public Result queryById(Long id) {
        //缓存穿透
        Shop shop = cacheClient.queryWithPassThrough(CACHE_SHOP_KEY, id, Shop.class, this::getById,CACHE_SHOP_TTL, TimeUnit.MINUTES);
        //互斥锁解决缓存击穿
//      Shop shop = queryWithMutex(id);
//      Shop shop = cacheClient.queryWithLogicalExpire(CACHE_SHOP_KEY, id, Shop.class, this::getById, 20L, TimeUnit.SECONDS);
        //4.不存在，返回错误
        if(shop==null){
            return Result.fail("店铺不存在");
        }
        //3.存在，返回店铺
        return Result.ok(shop);
    }

    private static final ExecutorService CACHE_REBUILD_EXECUTOR= Executors.newFixedThreadPool(10);
//    public Shop queryWithLogicalExpire(Long id){
//        String key=CACHE_SHOP_KEY+id;
//        //1.从redis查询店铺
//        String shopJson = stringRedisTemplate.opsForValue().get(key);
//        //2.判断店铺是否存在
//        if(StrUtil.isBlank(shopJson)){
//            //3.存在，返回
//            return null;
//        }
//        //4.命中，需要先把json反序列化成对象
//        RedisData redisData = JSONUtil.toBean(shopJson, RedisData.class);
//        JSONObject data = (JSONObject) redisData.getData();
//
//        Shop shop = JSONUtil.toBean(data, Shop.class);;
//        LocalDateTime expireTime = redisData.getExpireTime();
//        //5.判断是否过期
//        if (expireTime.isAfter(LocalDateTime.now())) {
//            //5.1未过期，返回店铺信息
//            return shop;
//        }
//        //5.2过期，需要缓存重建
//        //6.缓存重建
//        //6.1 获取锁
//        String lockKey=LOCK_SHOP_KEY+id;
//        boolean isLock = tryLock(lockKey);
//        //6.2判断是否获取锁成功
//        if (isLock){
//            //TODO 成功，开启独立线程
//                CACHE_REBUILD_EXECUTOR.submit(() -> {
//                    try {
//                        this.saveShop2Redis(id, 20L);
//                    }catch (Exception e){
//                        throw new RuntimeException(e);
//                    }finally {
//                        unlock(lockKey);
//                    }
//            });
//        }
//        //6.3获取锁成功， 开启独立线程进行缓存重建
//        //6.4返回过期的商铺信息
//        return shop;
//    }

//    public Shop queryWithMutex(Long id){
//        String key=CACHE_SHOP_KEY+id;
//        //1.从redis查询店铺
//        String shopJson = stringRedisTemplate.opsForValue().get(key);
//        //2.判断店铺是否存在
//        if(StrUtil.isNotBlank(shopJson)){
//            //3.存在，返回
//            return JSONUtil.toBean(shopJson, Shop.class);
//        }
//
//        if (shopJson != null ) {
//            return null;
//        }
//        //实现缓存重建
//        //1.获取互斥锁
//        String lockKey="lock:shop:"+id;
//        Shop shop = null;
//        try {
//
//
//            boolean isLock = tryLock(lockKey);
//            //2.判断是否获取成功
//            if (!isLock) {
//                //3.失败，休眠重试
//                Thread.sleep(50);
//                return queryWithMutex(id);
//            }
//
//            //4.不存在，查询数据库
//             shop = getById(id);
//            //模拟重建延时
//            Thread.sleep(200);
//            //5.判断店铺是否存在
//            if (shop == null) {
//                //6.不存在，写入空值
//                stringRedisTemplate.opsForValue().set(key, "", 2L, TimeUnit.MINUTES);
//
//                return null;
//            }
//            //6.存在，写入redis
//            stringRedisTemplate.opsForValue().set(key, JSONUtil.toJsonStr(shop), 30L, TimeUnit.MINUTES);
//        }catch (InterruptedException e){
//            throw new RuntimeException(e);
//        }finally {
//            //8.释放互斥锁
//            unlock(lockKey);
//        }
//        //7.存在，返回店铺
//        return shop;
//    }
//    public Shop queryWithPassThrough(Long id){
//        String key=CACHE_SHOP_KEY+id;
//        //1.从redis查询店铺
//        String shopJson = stringRedisTemplate.opsForValue().get(key);
//        //2.判断店铺是否存在
//        if(StrUtil.isNotBlank(shopJson)){
//            //3.存在，返回
//            return JSONUtil.toBean(shopJson, Shop.class);
//        }
//
//        if(shopJson.equals("")){
//            return null;
//        }
//        //4.不存在，查询数据库
//        Shop shop = getById(id);
//        //5.判断店铺是否存在
//        if(shop == null){
//            //6.不存在，写入空值
//            stringRedisTemplate.opsForValue().set(key,"",2L, TimeUnit.MINUTES);
//            //6.不存在，返回错误
//
//            return null;
//        }
//        //6.存在，写入redis
//        stringRedisTemplate.opsForValue().set(key,JSONUtil.toJsonStr(shop),30L, TimeUnit.MINUTES);
//        //7.存在，返回店铺
//        return shop;
//    }


//    private boolean tryLock(String key){
//        Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(key, "1", 10, TimeUnit.SECONDS);
//        return BooleanUtil.isTrue(flag);
//    }
//    private void unlock(String key){
//        stringRedisTemplate.delete(key);
//    }
//
//    public void saveShop2Redis(Long id,Long time) throws InterruptedException {
//        Shop shop = getById(id);
//        Thread.sleep(200);
//        RedisData redisData = new RedisData();
//        redisData.setData(shop);
//        redisData.setExpireTime(LocalDateTime.now().plusSeconds(time));
//        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY+id,JSONUtil.toJsonStr(redisData));
//    }

    @Transactional
    @Override
    public Result update(Shop shop) {
        Long id=shop.getId();
        //1.判断店铺是否存在
        if(id == null){
            return Result.fail("店铺不存在");
        }
        //1.更新数据库
        updateById(shop);
        //2.删除缓存
        stringRedisTemplate.delete(CACHE_SHOP_KEY+id);
        //3.返回
        return Result.ok();
    }

    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        if (x==null || y==null){
            // 根据类型分页查询
            Page<Shop> page = shopService.query()
                    .eq("type_id", typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
            // 返回数据
            return Result.ok(page.getRecords());
        }
        //计算分页参数
        int from = (current-1)*SystemConstants.DEFAULT_PAGE_SIZE;
        int end = current*SystemConstants.DEFAULT_PAGE_SIZE;
        //查询redis 按照距离排序，分页
        String key = SHOP_GEO_KEY+typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo().search(
                key,
                GeoReference.fromCoordinate(x, y),
                new Distance(5000),
                RedisGeoCommands.GeoSearchCommandArgs.newGeoSearchArgs().includeDistance().limit(end)
        );
        if (results == null){
            return Result.ok(Collections.emptyList());
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> list = results.getContent();
        if(list.size() <= from){
            return Result.ok(Collections.emptyList());
        }
        //截取from-end部分
        List<Long> ids = new ArrayList<>(list.size());
        Map<String,Distance> distanceMap = new HashMap<>(list.size());
        list.stream().skip(from).forEach(item -> {
            String shopIdStr = item.getContent().getName();
            ids.add(Long.valueOf(shopIdStr));
            Distance distance = item.getDistance();
            distanceMap.put(shopIdStr,distance);
        });
        //根据id查询shop
        String idStr = StrUtil.join(",", ids);
        List<Shop> shops = query().in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list();
        for(Shop shop:shops){
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        }
        return Result.ok(shops);
    }
}
